Mathematical device.



No. 666,070. Patented lan. I5, |90I. 0. SCHLEICHER.

MATHEMATICAL DEVICE.

(Application med oct. 2o, 19oo.\

(Nu Nadel.)

UNITED STATES PATENT OEEICE.

OTTO SCI-ILEICI-IER, OF CINCINNATI, OHIO.

MATH EMTICAL DEVEGE.

SPECIFICATION forming part of Letters Patent No. 666,070, dated January 15, 1901.

Application filed October 20, 1900. Serial No. 33,797. (No model.)

To all whom, t may concern,.-

Beit known that LOTTO ScHLEioHER,a citt zen of the United States, residing at Cincinnati,in the county of Hamilton, State of Ohio, have invented and produced a new and original Configuration of an Article of Manufacture of a Mathematical Device, of which the following is a specification, reference being had to the accompanying drawings.

Figure A is a dial arrangement consisting of figures for the purpose of furnishing the total amount multiplied or divided.

Fig. B serves as a sector wherewith to multiply or divide.

For example, to multiply twelve times twenty-seven bring the sector-letter B 7 under the figure 27 on dial lettered A. In the next right-hand column under the iigure 28, immediately in front of the figure l2 on the dial 13, Will be found the correct answer, 324. For division the rule is -j ust the reverse, as twenty-seven into three hundred and twenty-i`our goes twelve times. This mode of operation applies to all the different figures on the card.

I-Iaving described my invention, what I claim as new, and desire to secure by Letters Patent, is-

In a calculator, a disk having a series of igures in radial rows and in concentric circles, a pivot in the center of said circles, a sector of a circular disk revolubly mounted on said pivot and extended to cover all except tlie outside concentric circle of figures, said sector also having a radial row of iigures, said tigures on the sector corresponding in distance from the center with the figures on the disk, any ligure on the disk eX- cepting those in the outer circle being equal to the product of the figure in the outer circle in the radial row next to the left multiplied by the figure on the sector in the same circle, substantially as described.

In testimony whereof I have signed my name to this application in the presence of two witnesses.

OTTO SCHLEICHER.

Witnesses:

E. H. BAKER, W. C. HILL. 

